Hi Tom,

If you are a student, you can get the student version that is good for 3 years.  If not, I would get in touch with Autodesk to see if you can get the remainder of your 30 day trial.  You can chat with them online from this link 

http://knowledge.autodesk.com/contactus/activation-registration/activating-product/serial-numbers-an...

Good Luck!